1. Field of the Invention
The present invention relates to a rear holder.
2. Description of the Related Art
In a related art connector including a cylindrical housing and a connector terminal inserted into the housing, there has been known a structure that a rear holder is attached to a wire lead-out opening at one end of the housing so that an electric wire connected to the connector terminal can be led out through a through hole of the rear holder (see JP-A-2012-185960).
According to the rear holder, the electric wire is inserted into the through hole smaller than the wire lead-out opening of the housing so that motion of the electric wire can be restricted. Thus, for example, the electric wire can be prevented from being damaged, or the connector terminal can be prevented from slipping off from the housing due to the motion of the electric wire.
In recent years, such a connector using a rear holder is often used in a part where electric wires of a wire harness mounted in an electric car, a hybrid car or the like are connected to each other.
A high voltage cable or the like is used as such an electric wire mounted on a car. For example, a measure taken to prevent foreign substances from invading the housing from a gap between the inner circumferential surface of the through hole of the rear holder and the outer circumferential surface of the high voltage cable passing through the through hole is requested in order to secure desired safety. For example, IP (International Protection) standards may be used as criteria for determining the safety of the connector. In order to satisfy requirements of the IP standards, it is, for example, required that, when a wire of a predetermined thickness (e.g. φ1 mm) is inserted into a gap between the inner circumferential surface of the through hole of the rear holder and the outer circumferential surface (insulating jacket) of the high voltage cable passing through the through hole, the wire cannot touch a live part such as a connector terminal through the gap.
However, the size of the gap changes in accordance with a variation in outer diameter of the electric wire, a variation in hole diameter of the through hole of the rear holder, etc. According, it is, for example, necessary to set the hole diameter of the through hole of the rear holder to be smaller in consideration of those variations. However, when the through hole is set to be smaller, a load with which an electric wire formed with a large outer diameter is inserted into the through hole of the rear holder increases to lower the working efficiency.
There is known another structure in which a rear holder is formed as a pair of half cylindrical parts divided axially, and the rear holder holding an electric wire between the half cylindrical parts is inserted and fixed to a wire lead-out opening of a housing. However, even in such a rear holder, for example, when the electric wire is formed with a large outer diameter, a load with which the rear holder is inserted into the wire lead-out opening of the housing may increase to lower the working efficiency.